Is Law prepared to somebody leaving Earth regardless of the Outer Space Treaty?

Question

I've read two other questions about Legality of space colonization and Am I legally allowed to build my own rocket and fly to space by myself?. And I'd like to raise the stakes from those questions.

Imagine a capable group of people, who have all that it takes to fly away to Mars and settle there. They obtain no permit from any Country, they launch from International waters and ignore Outer Space Treaty.

What would be their legal status on Mars from our perspective?

It would be ultimately costly and time consuming even to try to return them to Earth to convict. Moreover, they may declare Mars as their property and there will be no way to object that claim.

Answer 1

Yes the law encompasses this

Each individual would remain a citizen of their respective country or countries and subject to their laws and jurisdiction.

The vessel (and any colony it created) would be subject to the laws of its country of registration, or if not registered, the laws of the country of the ship it was launched/transported on.

While anyone is free to explore space, no nation can claim sovereignty so their claim would not be recognised.